"American and other coalition forces here are being killed in increasing numbers by the very Afghan soldiers they fight alongside and train, in attacks motivated by deep-seated animosity between the supposedly allied forces, according to American and Afghan officers and a classified coalition report obtained by The New York Times."

It adds that "although NATO does not release a complete tally of its forces' deaths at the hands of Afghan soldiers and the police, the classified report and coalition news releases indicate that Afghan forces have attacked American and allied service members nearly three dozen times since 2007."

Also today, a NATO helicopter crashed in southern Afghanistan's Helmand province — killing six military personnel. Though commanders haven't yet released more information, NPR, NBC News, The Associated Press and some other outlets are reporting they've been told by military sources that the six were U.S. Marines. Also, NBC reports, "officials said there were no signs of enemy activity in the area at time of the crash."